I will say that as most products of considerably long speedrunning sessions, that demo looks a little miraculous, with many things magically falling into place. Yes, the timing couldn't have been luckier.
I cannot comment on the XDRE output as I don't understand the Doom demo format, but DSDA hosts almost 500 demos recorded by me for anyone to make a judgement on whether these patterns belong to my playing style.
After seeing your post I managed to record this (attached) 0:37 *.lmp with 97% in ZDoom 2.8.1 relatively quickly. It flows very similarly to the demo I posted before. I might attempt a better run in ZDoom with less hiccups, but I understand it won't be conclusive or anything, especially due to the engine differences. I don't know what can be done here. That's really the problem with the contest's format, as highlighted in that post rdwpa quoted above.